FIRESTONE by Mark Reynolds

Sealed inside a glowing stone, a flame of potent magic burns, waiting to be released, craving to be controlled…
For Kai Kazami, life is almost perfect. He’s a carefree carpenter who married the girl of his dreams. But the day he turns thirty, fate throws a curveball that rips Kai’s world apart.
His wife is missing. His mother is dead. A third tragedy is on the way, one which could push Kai to mental collapse, or guide him on a path to unimaginable abilities.
To save his wife and honor his mother, Kai must solve the puzzle, yet his only clues are a cryptic message, and a mysterious stone teeming with power…